1. Field of the Invention
The present invention relates to photographic processors and more specifically to processors for treating flat discrete elements of photographic film, particularly such elements having a disc shaped configuration.
2. Description of the Prior Art
Photographic processors are well known for use with film in a web format whereon image areas are disposed side by side along the length of the web. In a typical low volume processor such webs are wound on a reel and supported in such a manner that adjacent convolutions around the reel are not in physical contact. The reels may be placed in one or more tanks of processing solution and rotated in the solutions. Relative movement between the film and the processing solution improves the uniformity of development and displaces any foreign matter that may cling to the film. In a typical medium volume processor a number of such webs are suspended on racks which are successively dunked in tanks of processing solution. In this case, relative movement between the solution and the film is provided by mechanically agitating the solution. One agitating means, known as sparging, involves the introduction of bursts of gas, such as nitrogen, at the bottom of the tank. In larger volume processors, the webs are spliced together, end-to-end, and are continuously transported on rollers through a series of tanks containing the processing solutions. Transporting the film through the solutions provides some relative movement between the film and the solution.
In addition, means such as sparging have been employed in continuous web processors. In all of the processors noted above, it is desirable, at various stages in the process, to remove any excess solution that may be clinging to the webs. Removal of excess solution between successive treatments, for example, reduces inter solution contamination, and removal of excess solution before final drying permits the use of higher drying temperatures without causing rills or pits on the emulsion surface. Removal of this excess solution has been accomplished by various means such as sponges, air knives, and, most frequently, by means of a rubber squeegee blade. Such mechanical squeegeeing involves possibly detrimental mechanical contact with the image area of the film. After processing and printing, the webs are cut for return, along with the prints, to the customer.
Processors for discrete film units, especially in a disc format, are less well known, although versions of film discs and cameras that used them were first developed some time ago. The scarcity of the prior art of automatic processors for discrete elements of photographic film may indicate that the earlier versions of film discs were processed individually by hand or by some other labor intensive process.
More recently, discrete film elements having a generally disc shaped format have been developed for use in modern cartridges, and cameras adapted to utilize such cartridges have been developed. Such cameras and cartridges are more fully disclosed in the referenced U.S. patent applications Ser. No. 774,715 and Ser. No. 774,716, respectively. The film elements include a central hub of molded plastic that is permanently attached to a disc of photographic film. The molded hub has a central opening that includes a keyed hole by which the hub is adapted to be rotationally supported within the camera. Indexing ears on the molded hub are used for positioning successive exposure areas of the film in the exposure gate of the camera. After exposure, the film unit is adapted to be removed from the cartridge for processing. Since the camera and film unit were designed to be pocketable, the exposure areas on the film unit are relatively small. With such a small format, it becomes increasingly critical to avoid scratches and other defects in the image area of the film, since such defects would be greatly magnified during printing. Therefore in processing such film elements, it has been found to be extremely important to avoid any mechanical contact with the image areas of the film element to minimize the possibility of scratching the image area.
It is known in the art to process non-web format film, such as plate or rectangular sheets of film by attaching the film sheets to the periphery of a drum and rotating the drum in a tray of processing solution. See U.S. Pat. No. 3,693,529. It is also known to attach photographic plates to a carrier and rotate the carrier in a container of processing solution about an axis passing through the center of the plates. See U.S. Pat. No. 608,871. It is further known to attach plates to a circular disc and rotate the disc about its center in a container of processing solution. See U.S. Pat. No. 750,621. It is also known to remove excess processing solution and to dry film chips, such as dentral x-ray film, by clipping rectangular film chips to the periphery of a disc and after processing the film chips, by rotating the disc about its axis on a dental lathe. See U.S. Pat. No. 2,766,670.